Multimedia services are foreseen to bring new revenues to the cellular operators running either or both 3G WCDMA and 2.5 G GSM networks. Since plain circuit voice will be an important source of revenue still for many years, the market is developing services ‘beyond’ voice. These are multimedia applications that for example includes a normal voice call but add another media in parallel to that speech call, so that the two mobile users can both talk and visually share another media at the same time. This shared media may be a still image, a 1-way live video, text or game. This type of shared services we herein call Shared Multimedia (SMM) services.
Shared multimedia services requires that a user terminal, e.g. a mobile phone, is capable of running both a standard circuit switched voice call and a packet switched IP session at the same time, besides hosting the client that makes up the application logic.
A highly wanted feature by operators is that mobile users can e.g. visually see from their phone display, which—if any, Shared Multimedia services that are applicable within the ongoing voice call. If the remote user and the calling user both have the capability to use one or several shared multimedia services, one or several icons could be enlightened in the display of both user's mobile phones. This type of capability check we herein call the shared multimedia capability discovery process.
However, the de-facto capability discovery solution discussed currently in standardisation, is oriented around letting the mobile phone initiate a packet switched based mobile capability check towards the remote mobile phone, just after the voice call has been established. This means that a capability discovery check will take place over the radio interface for all mobile-mobile calls, irrespective of whether or not the remote user has the SMM capability.
The problem lies with finding a mobile capability discovery method that is optimised from a radio resources perspective. Hence, the capability discovery process and results should only be passed over the radio interface when absolutely necessary and unavoidable. Thus, the capability discovery mechanism shall not be invoked in mobile-to-non-mobile voice calls and it shall not be invoked for not SMM-capable mobile phones or for users who are not allowed to use the service even though their mobile phones has the capability technically.
A user terminal uses a packet-switched IP session to send a capability query message from the initiating terminal to the other terminal. The packet switched IP session uses radio resources. This means that a query has to be initiated in the beginning of every phone call to determine if one of the two terminals supports SMM. The probability that both terminals support SMM will however be very low for many years. Therefore, a lot of radio traffic over the capacity limited radio interface will be generated unnecessarily.
Thus, one object is to provide a method and a system for Multimedia Capability discovery that avoids unnecessary use of the radio interface and resource.
Yet another object is to provide a solution to the problem to discover if a called User terminal supports Shared Multimedia service if the service is based on other technologies than IP multimedia subsystem (3GPP IMS), for example MMS technology.